There are no interference problems with fiber optic cables and power cables. Fiber uses light for data transmission. Electrical Interference: Electrical cables can produce electromagnetic. As long as the 14g wire doesn't damage the fiber, everything is fine, As long as the fiber sheath is non conductive (small fiber is always going to be), the code permits it to be run in conduits and elsewhere along side of power wiring. The two can be installed side by side without any significant. The high-speed fiber optic data must be converted to electrical signals before the data can be transmitted to the home on the existing copper cable or phone line DSL. No more "Almost" Good Answers.